using Microsoft.Extensions.DependencyInjection;
using StellaOps.Policy.Engine.Storage.Mongo.Internal;
using StellaOps.Policy.Engine.Storage.Mongo.Migrations;
using StellaOps.Policy.Engine.Storage.Mongo.Options;
using StellaOps.Policy.Engine.Storage.Mongo.Repositories;

namespace StellaOps.Policy.Engine.Storage.Mongo;

/// <summary>
/// Extension methods for registering Policy Engine MongoDB storage services.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Adds Policy Engine MongoDB storage services to the service collection.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configure">Optional configuration action for PolicyEngineMongoOptions.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPolicyEngineMongoStorage(
        this IServiceCollection services,
        Action<PolicyEngineMongoOptions>? configure = null)
    {
        ArgumentNullException.ThrowIfNull(services);

        // Register options
        if (configure is not null)
        {
            services.Configure(configure);
        }

        // Register context (singleton for connection pooling)
        services.AddSingleton<PolicyEngineMongoContext>();

        // Register migrations
        services.AddSingleton<IPolicyEngineMongoMigration, EnsurePolicyCollectionsMigration>();
        services.AddSingleton<IPolicyEngineMongoMigration, EnsurePolicyIndexesMigration>();
        services.AddSingleton<IPolicyEngineMongoMigration, EnsureExceptionIndexesMigration>();

        // Register migration runner
        services.AddSingleton<PolicyEngineMigrationRunner>();

        // Register initializer
        services.AddSingleton<IPolicyEngineMongoInitializer, PolicyEngineMongoInitializer>();

        // Register dynamic collection initializer for effective findings
        services.AddSingleton<IEffectiveFindingCollectionInitializer, EffectiveFindingCollectionInitializer>();

        // Register repositories
        services.AddSingleton<IExceptionRepository, MongoExceptionRepository>();

        return services;
    }

    /// <summary>
    /// Adds Policy Engine MongoDB storage services with configuration binding from a configuration section.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configuration">Configuration section containing PolicyEngineMongoOptions.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPolicyEngineMongoStorage(
        this IServiceCollection services,
        Microsoft.Extensions.Configuration.IConfigurationSection configuration)
    {
        ArgumentNullException.ThrowIfNull(services);
        ArgumentNullException.ThrowIfNull(configuration);

        services.Configure<PolicyEngineMongoOptions>(configuration);

        return services.AddPolicyEngineMongoStorage(configure: null);
    }
}